BOSTON, Nov 18 (Reuters) - U.S. biotechnology company
Genzyme Corp GENZ.O reported more bad news on Wednesday,
announcing it is dropping development of its experimental
kidney disease drug after it proved no more effective than the
company's existing drug Renvela.

The news comes as the company is struggling to resolve a
series of manufacturing problems that have led to a shortage of
its biggest-selling drug, Cerezyme, a treatment for Gaucher
disease, a rare genetic disorder that can cause
life-threatening organ damage.

Genzyme's shares fell 1.5 percent to $49.57 in early
trading on Nasdaq.

Cambridge, Massachusetts-based Genzyme said it had hoped to
develop a drug that was more potent than Renvela, itself a
successor to the company's kidney disease drug Renagel. The
active ingredient in the drugs is known as sevelamer.

Renvela treats hyperphosphatemia, or excess phosphate in
the blood, a risk factor for cardiovascular disease in patients
with chronic kidney disease.

"This is a very significant negative in our view," said
Christopher Raymond, an analyst at Robert W. Baird, in a
research note. "With Renagel/Renvela patent expiry in 2014,
this program was seen as the primary vehicle to extend
Genzyme's $850 million renal franchise."

Genzyme had been studying its new drug, an advanced
phosphate binder, in 349 patients. The trial was in mid-to-late
stage development.

"Without line extension for the Renagel-Renvela franchise,
we estimate nearly $1 billion in sales is at risk for Genzyme
looking to 2014," said Geoffrey Meacham, an analyst at J.P.
Morgan, in a research report. "We view the franchise as
vulnerable to generic sevelamer competition, which we assume
will dominate the phosphate binder market in 2014."